diff --git a/src/binary.cpp b/src/binary.cpp
index b987375..4db6d0b 100644
--- a/src/binary.cpp
+++ b/src/binary.cpp
@@ -1,6 +1,6 @@
 #include "yaml-cpp/binary.h"
 
-#include <ctype.h>
+#include <cctype>
 
 namespace YAML {
 static const char encoding[] =